# Friction in Collision Investigations (CSR 104)

This course is intended to discuss how the basic elements involved with friction allow an investigator to appropriately determine the coefficient of friction. The determination of friction will then allow for the determination of braking efficiencies and other mechanical conditions at the time of a collision.

This course consists of two (2) video lessons and will include an assessment at the conclusion of each lesson.

Credit: 2 hrs.

**Friction in Collision Investigations, Part 1**

**Lesson Purpose:** This lesson is intended to discuss how the basic elements involved with friction allow an investigator to appropriately determine the coefficient of friction. The determination of friction value and various influences on the value are also discussed.

**Training Objectives:** At the end of this lesson, the student will be able to achieve the following objectives in accordance with the information received in class:

1. Define Friction.

2. Demonstrate an understanding of the dynamics of friction as a component of a tire and roadway surface to interact against each other.

3. Understand the basic concepts surrounding friction.

4. Understand how slope is determined by the rate of change in the rise over the run in roadway variances.

5. Determine the influences of different types of friction and how that will affect calculated coefficients of friction.

Video Length: 00:10:52

**Friction in Collision Investigations, Part 2**

**Lesson Purpose: **This lesson is intended to discuss how the friction value used in calculations can change with braking efficiencies and resultant drag factors. Braking efficiencies and drag factor calculations are discussed and performed.

**Training Objectives:** At the end of this lesson, the student will be able to achieve the following objectives in accordance with the information received in class:

1. Understand how the condition of the vehicle could contribute to the collision in the investigation.

2. Understand and determine the dynamic movement of the individual tires during the collision sequence.

3. Understand the concepts of braking efficiency and resultant drag factor.

4. Understand how to calculate braking efficiencies and resultant drag factors.

Video Length: 00:12:43